1. Field of Invention
The present invention relates to a golf club and a manufacturing method therefor, particularly to a head and method of manufacturing thereof.
2. Prior Art
Conventionally, not only steel and titanium alloy but also copper or copper alloy has been used for the material of a golf club such as iron golf club. For such copper alloy, Japanese Patent Un-Examined Publication No. 63-267376 proposed to use beryllium copper alloy. Beryllium copper alloy which has a good flexibility as taught by the publication, has been used, for example, for adjustment of weight distribution, taking advantage of its relatively large specific gravity. On the other hand, Japanese Patent Un-Examined Publication No. 8-294553 taught that an annular head body made of beryllium copper comprises a face member made of less dense material than beryllium copper, such as aluminum alloy, said face member being pressed into the inside of the head body. This aimed at enlarging a sweet area, i.e., an area on the face where balls can travel comparatively straight and well when struck thereupon, through the dispersion of the weight of the head toward its periphery.
In general, beryllium copper is yellow, having an appearance more bright and lustrous than copper, and thus such appearance is preferred by people. However, beryllium copper is liable to get blackish due to corrosion, so that its gloss is lost soon or later. At that stage, its appearance would lack in attractiveness. Particularly for golf clubs, they are used outdoors and given impacts in striking balls. In other words, they are often scratched and damaged not only by impacts of balls, but also by strong contacts with lawn, green and the like which include moisture and agricultural chemicals, so that corrosion proceeds more rapidly. The problem of corrosion is perceived not only in beryllium copper but also in copper and other types of copper alloy.
For a means for preventing such corrosion, wax-coating was proposed, which, however, has such a poor durability that golf clubs thus coated would be liable to cause the problems of the damage and/or the stripping off of the coating under the above-mentioned severe condition in using the same.
Whereas, with the golf club head utilizing a combination of beryllium copper with aluminum alloy or the like, as disclosed in the aforesaid Japanese Patent Un-Examined Publication No. 8-294553, there is another problem that aluminum alloy causes an electrification corrosion, such as so-called galvano-corrosion. Galvano-corrosion is caused, for example, due to a kind of a battery being formed between two different metals, one being a noble metal, the other a base metal.